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* Copyright (c) 2009, The University of Texas at Austin
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using System;
using System.Collections.Generic;

namespace Bio.Data.Interfaces
{
    /// <summary>
    /// An RNA secondary structure base pair
    /// </summary>
    public interface IBasePairBioEntity
    {
        /// <summary>
        /// The index (within the sequence) of the five prime nucleotide in the base pair
        /// </summary>
        int FivePrimeIndex { get; }

        /// <summary>
        /// The five prime nucleotide in the base pair
        /// </summary>
        IBioSymbol FivePrimeNucleotide { get; }

        /// <summary>
        /// The index (within the sequence) of the three prime nucleotide in the base pair
        /// </summary>
        int ThreePrimeIndex { get; }

        /// <summary>
        /// The three prime nucleotide in the base pair
        /// </summary>
        IBioSymbol ThreePrimeNucleotide { get; }

        /// <summary>
        /// Textual representation of the base pair
        /// </summary>
        string Text { get; }
    }

    public class BasePairComparer : IEqualityComparer<IBasePairBioEntity>
    {
        #region IEqualityComparer<IBasePairBioEntity> Members

        public bool Equals(IBasePairBioEntity x, IBasePairBioEntity y)
        {
            if (x == null || y == null) return false;
            if (x.FivePrimeNucleotide == null || x.ThreePrimeNucleotide==null) return false;
            return ((x.FivePrimeIndex == y.FivePrimeIndex) && 
                    (x.ThreePrimeIndex == y.ThreePrimeIndex) &&
                    (x.FivePrimeNucleotide == y.FivePrimeNucleotide) &&
                    (x.ThreePrimeNucleotide == y.FivePrimeNucleotide)) ? true : false;
        }

        public int GetHashCode(IBasePairBioEntity obj)
        {
            return obj.GetHashCode();
        }

        #endregion
    }
}
